Iceberg size of Greater London breaks off Antarctica.

Extract from The Guardian

Antarctica

The 1,270sq km chunk separated from Brunt Ice Shelf near a British Antarctic Survey station on Friday.

The Brunt Ice Shelf in Antarctica in January 2020. The separation occurred just over 20km from Britain’s Halley research station.

Sarah Marsh

@sloumarsh

Sat 27 Feb 2021 05.33 AEDT

Last modified on Sat 27 Feb 2021 05.48 AEDT

An iceberg almost the size of Greater London has split off from Antarctica, near a British Antarctic Survey station.

The separation occurred just over 20km from Britain’s Halley research station but there was no one in the base and so there was no risk to human life. The 1,270 sq km, 150-metre-thick chunk of frozen water separated from the Brunt Ice Shelf on Friday.

The British Antarctic Survey (BAS), which has been operating Halley in a reduced role since 2017 because of the concern an iceberg could imminently split off, captured footage of large cracks at Antarctica’s Brunt Ice Shelf earlier in the month.

Large cracks in the ice of this part of Antarctica were first discovered a decade ago and, since then, the BAS has been monitoring the area in case of just such an event. BAS has a range of GPS devices on the Brunt. These relay information about ice movements back to the agency’s headquarters in Cambridge.

Adrian Luckman, British glaciologist and professor of geology at Swansea University in Wales, has been examining images of the brunt in recent weeks and estimating when a large chunk of ice might break off from the glacier.

“Although the breaking off of large parts of Antarctic ice shelves is an entirely normal part of how they work, large calving events such as the one detected at the Brunt Ice Shelf on Friday remain quite rare and exciting,” the remote-sensing expert told the BBC. “With three long rifts actively developing on the Brunt Ice Shelf system over the last five years, we have all been anticipating that something spectacular was going to happen.

“Time will tell whether this calving will trigger more pieces to break off in the coming days and weeks. At Swansea University we study the development of ice shelf rifts because, while some lead to large calving events, others do not, and the reasons for this may explain why large ice shelves exist at all.”